Move SCL compiler warming up from plugin activator to SimanticsPlatform startup
Warming up SCL compiler in plugin activator caused excess output to stdout when running org.eclipse.equinox.p2.director application with -listInstalledRoots option. This is problematic e.g. for Simupedia Manager when resolving service names.
Plugin dependencies have changed in Simantics platform due to command recording implementation. This has not been a problem prior to that.